[Serusers] how to restrict registration

Hi all, I would like to restrict registration based on IP in Contact, something like: foo(a)bar.com --> allowed contact IP are 192.168.1.10 or 192.168.1.15 boo(a)bar.com --> allowed contact IP are 192.168.1.20 or 192.168.1.30 I tried with permissions module: if (!allow_register("register.allow", "register.deny")) { sl_send_reply("403", "Permission denied"); break; }; and # content of register.allow "^sip:foo@.*$" : "^sip:.*192\.168\.1\.10$" "^sip:foo@.*$" : "^sip:.*192\.168\.1\.15$" "^sip:boo@.*$" : "^sip:.*192\.168\.1\.20$" "^sip:boo@.*$" : "^sip:.*192\.168\.1\.30$" but it doesn't work. SER lets foo@ and boo@ register using whatever IP they want to. Where is the mistake? Am I missing something? Thank you Ciao FF